/****************************************************************
 * BiffSocko                                    8/4/2004
 * logger.c
 * 
 * This program essentially acts as a logging devise for other programs.
 * normally a shell script (or another c/perl/java program) would call this
 * program with the following arguements:
 *
 * <calling program name> <logfile> <STOP | START> [MESSAGE]
 * where MESSAGE can be any text
 * NOTE: STOP or START has to be in caps.
 *
 * the calling program should call logger.c at the begining of the
 * program or script with the START parameter.  It should then 
 * call logger.c at the end of it's run with the STOP parameter.
 * 
 * if you are using logger.c with lots of scripts and programs and a 
 * single logfile, it is advised that you use logger.c to update a temp 
 * logfile and then after the program run copy the contents of the temp 
 * logfile into the real one:
 *
 * example:
 *
 * #!/bin/sh
 * LOGFILE="/var/log/pgmlog"
 * TMPLOGFILE="/tmp/pgmlog.$$"
 * logger $0 $TMPLOGFILE START
 * # do some stuff
 * logger $0 $TMPLOGFILE STOP
 * cat $TMPLOGFILE >> $LOGFILE
 * rm $TMPLOGFILE
 *
 * the output will appear as follows:
 * 
 * program_name START DATE DATE_in_seconds STOP DATE DATE_in_seconds
 *
 * DATE_in_seconds refers to the number of seconds that have passed since
 * Jan. 1 1970 (standard UNIX format for time)
 *
 * this program will exit with 0 upon success and -1 if it fails
 * 
 * TO COMPILE:
 * gcc -o logger logger.c
 ****************************************************************/

#include <strings.h>
#include <stdio.h>
#include <time.h>

#define max 80
#define usage "pslogger <program> <logfile> <START|STOP> [ MESSAGE ]"

int main (int argc, char *argv[])
{

	/********************************
	 * some variables
	 ********************************/
	int flag=0;
	char LocalTime[max]; /* just a place ta keep the time*/
	struct tm *LOCtm;
	time_t clock;        /* holds num of seconds since jan 1 1970 */
	time_t error_time;
	size_t error_chk;
	char program[max];
	char logfile[max];
	char state[max];
	char message[max];
	FILE *Fp=NULL;	    /* LOGFILE*/


	/******************************************
	 * make sure we get the right parameters 
	 ******************************************/
	if((argc != 4) && (argc != 5)){
                printf("%s\n", usage);
                exit(-1);
        }

	strcpy(program,argv[1]);
	strcpy(logfile,argv[2]);
	strcpy(state,argv[3]);

	if(argc == 5){
		strcpy(message, argv[4]);
		flag=1;
	}
	
	if((strcmp(state, "START") != 0) && (strcmp(state, "STOP") != 0)){
		printf("wrong state %s\n", state);
		exit(-1);
	}


        /*********************************************************
         * get number of seconds from Jan 1, 1970 (time function)
         * and then convert it to Local Time
         *********************************************************/
        error_time = time(&clock);
        if(error_time == -1){
                fprintf(stderr, "error getting time()\n");
                exit( -1);
        }

        LOCtm=localtime(&clock);


        /*********************************************************
         * strftime just formats the time into something useable
         *********************************************************/
        error_chk = strftime(LocalTime, max,"%d-%b-%y %H:%M", LOCtm);
        if ( error_chk == 0){
                fprintf(stderr, "error getting Local Time\n");
                exit( -1);
        }


	if(!(Fp=fopen(logfile, "a+"))){
		printf("can't open %s to write\n", logfile);
		exit(-1);
	}


        /*********************************************************
         * just print out the times and exit cleanly
         *********************************************************/
	if(flag == 0){
		if(strcmp(state, "START") == 0){
       			fprintf(Fp,"%s\t%s\t%s\t%i\t", program,state, LocalTime, clock);
	
		}else{
			fprintf(Fp,"%s\t%s\t%i\n", state, LocalTime, clock);
	
		}
	}else{
		if(strcmp(state, "START") == 0){
			fprintf(Fp,"%s\t%s\t%s\t%i\t%s", program,state, LocalTime, clock, message);
		}else{
			fprintf(Fp,"%s\t%s\t%i\t%s\n", state, LocalTime, clock, message);
		}
	}
			
	fclose(Fp);
        exit ( 0);
}